The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Many storage and communication devices use analog front-end circuits for signal processing. For example, in storage devices, such as magnetic disk drives and optical disc drives, read channels use analog front-end circuits to read and write data on storage mediums. In communication devices, transmitters and receivers use analog front-end circuits to transmit and receive signals.
The analog front-end circuits typically include data converters such as analog-to-digital converters and digital-to-analog converters. For example, in storage devices, analog-to-digital converters are used to convert data that is read from a storage medium from analog to digital format, and digital-to-analog converters are used to convert data that is to be written on the storage medium from digital to analog format. In communication devices, analog-to-digital converters are used to convert data that is received via a communication medium from analog to digital format, and digital-to-analog converters are used to convert data that is to be transmitted via the communication medium from digital to analog format.
Filters such as anti-aliasing filters and smoothing filters are often used in conjunction with data converters. For example, continuous time filters may be used to filter signals that are input to analog-to-digital converters and to filter signals output by digital-to-analog converters. The continuous time filters typically include discrete components and operational amplifiers designed using bipolar and/or field-effect transistors. These filters cannot be easily integrated with data converters in an integrated circuit using a single process due to considerations of cost, power consumption, and programmability. Further, harmonic distortion cannot be reduced below a certain limit in these filters due to nonlinearities of components used to manufacture these filters.